The present invention generally relates to adhesive medical dressings. More particularly, the present invention provides a medical dressing with multiple exposed adhesives, one of which includes a bioactive agent. The present invention also provides a masked adhesive transfer process.
The use of transparent film dressings continues to grow at an accelerated rate. In addition to their use as protective layers over wounds, where they facilitate healing in a moist environment while acting as a barrier to contaminating liquids and bacteria, the films are also used over catheters to prevent contamination of the catheter insertion site by contaminating liquids and bacteria. Dressings fitting the above description are available under a number of trade names such as TEGADERM(trademark) (3M Company, St. Paul, Minn.), BIOCLUSIVE(trademark) (Johnson and Johnson Company, New Brunswick, N.J.), and OP-SITE(trademark) (T. J. Smith and Nephew, Hull, England).
The adhesives used to secure the dressings in place on a patient are typically fairly aggressive, i.e., the adhesives have a high tack, to prevent unwanted release from a wound edge or catheter site. Many of the adhesives are also contact transparent to allow visual monitoring of wounds or catheter sites without removing the dressings.
One of the purposes of the dressings is to reduce or prevent infection of wounds or catheter sites. Attempts have been made to include antimicrobial agents in dressings to further improve the ability of dressings to reduce or prevent infection by reducing migration of infectious agents across the dressing surfaces. These attempts typically have significant drawbacks.
One approach to incorporating antimicrobial agents in medical dressings involves the inclusion of a pad that acts as a carrier for the antimicrobial agent. The pads, however, typically prevent visual monitoring of the wound or catheter site located directly beneath the pad. The pads are also typically not adhesive, i.e., they cannot adhere to the wound or catheter site. As a result, the dressing is not as firmly secured as a similar dressing that does not include a pad.
Other approaches have involved incorporating antimicrobial agents directly into the pressure sensitive adhesive used on a dressing, but this approach also suffers from drawbacks. For example, in those pressure sensitive adhesives that provide desired levels of tack to a patient""s skin (to, e.g., prevent edge lift off of the dressing), the antimicrobial agents are also bound so well that they are not available in effective concentrations at the wound or catheter site.
Pressure sensitive adhesive formulations incorporating antimicrobial agents that are available in effective concentrations at a wound or catheter site are known. See, e.g., U.S. Pat. Nos. 5,614,310 and 5,908,693 (both to Delgado et al.). These pressure sensitive adhesives, however, exhibit tack to skin that is reduced upon exposure to moisture such as, e.g., sweat, when in place on a patient. As a result, these pressure sensitive adhesives do not present good candidates for use as the only adhesive exposed on, e.g., medical dressings that require relatively high tack to reduce the likelihood of unwanted removal.
The present invention provides medical dressings that include multiple exposed pressure sensitive adhesives. One of the pressure sensitive adhesives includes a bioactive agent and is substantially contact transparent. It may also be preferred that all of the adhesives are substantially contact transparent.
Also provided are methods of manufacturing the medical dressings. By providing multiple exposed pressure sensitive adhesives, the pressure sensitive adhesive formulations can be varied to provide desired properties in different areas of the dressing. For example, one of the exposed pressure sensitive adhesives may exhibit relatively high tack to skin while another exposed pressure sensitive adhesive may serve as a vehicle for a bioactive agent while still providing some adhesive properties.
The term xe2x80x9csubstantially contact transparent,xe2x80x9d as used in connection with the present invention, means that, when adhered to a patient""s skin, a wound or catheter site can be visually monitored through those portions of the backing and pressure sensitive adhesive or adhesives in contact with the patient""s skin without requiring removal of the dressing. The term xe2x80x9cbioactive agent,xe2x80x9d as used in connection with the present invention, includes pharmacologically active ingredients, such as drugs, antibiotic agents, antimicrobial agents, etc.
In some embodiments, a pressure sensitive adhesive that exhibits relatively high tack to skin may be provided around the periphery of the dressing while a pressure sensitive adhesive incorporating a bioactive agent is provided in the center of the dressing. As a result, the edges of the dressing can be firmly secured to a patient, while the center of the dressing provides, e.g., a degree of infection control if the bioactive agent is antimicrobial. In other embodiments, a higher tack pressure sensitive adhesive may be provided at two opposing sides of the dressing with a bioactive adhesive located in between the opposing portions of higher tack adhesive.
The different adhesives may be applied directly to different areas of the dressing backing such that different areas of the backing include only one pressure sensitive adhesive. Alternatively, one or more of the pressure sensitive adhesives may be provided over one or more pre-applied areas of pressure sensitive adhesive such that the pressure sensitive adhesives are located in multiple layers over a portion of the dressing. In all cases, however, at least two different pressure sensitive adhesives are exposed on the bottom surface of the dressing. It is further preferred that all of the pressure sensitive adhesives are moisture vapor permeable and/or provided using techniques (e.g., pattern coating) that provide a desired level of moisture vapor permeability.
The present invention also provides methods of transferring adhesives using a mask such that the adhesive is transferred to selected areas of a receiving surface. The mask may be provided in the form of a liner including a plurality of voids formed therein. This method can provide precise control over registration of the transferred adhesive on the receiving surface, e.g., a backing. Registration control may be particularly important if the adhesive is transferred to, e.g., a backing and carrier composite including windows to facilitate delivery of the backing. In such a situation, it may be desirable to accurately register the transferred adhesive with, e.g., the windows in the carrier. Examples of such dressings are found in, e.g., U.S. Pat. No. 5,531,855 (Heinecke et al.).
In one aspect, the present invention provides a medical dressing having top and bottom surfaces, the medical dressing including a substantially contact transparent backing; a first pressure sensitive adhesive exposed on the bottom surface of the dressing; and a second pressure sensitive adhesive exposed on the bottom surface of the dressing, wherein the second pressure sensitive adhesive includes at least one bioactive agent and is substantially contact transparent.
In another aspect, the present invention provides a method of manufacturing a medical dressing having top and bottom surfaces by providing a substantially contact transparent backing; providing a first pressure sensitive adhesive that is exposed on the bottom surface of the dressing; and providing a second pressure sensitive adhesive that is exposed on the bottom surface of the dressing, wherein the second pressure sensitive adhesive includes at least one bioactive agent and is substantially contact transparent.
In another aspect, the present invention provides a method of transferring an adhesive to a substrate by providing a mask liner including a plurality of voids formed therein; locating a receiving surface proximate a first side of the mask liner, wherein at least a portion of the receiving surface is exposed through at least one of the plurality of voids in the mask liner; providing transfer adhesive on a transfer liner; and transferring at least a portion of the transfer adhesive to the portion of the receiving surface exposed through the void in the mask liner.
These and other features and advantages of the articles and methods of the present invention are discussed below.